Rapid calculator for use with carpenter&#39;s square



Aug. 22, 1950 W/. A. PETERSON v 2,519,

RAPID CALCULATORFOR USE WITH cARPEN'rEms SQUARE Filed Feb. s, 1948 y 2Sheets-Sheet 1 Jywwwtw V Val: er FL .1 e1: ETS an Aug. 22,1950 w. A.PETERSON 2,519,699

RAPID CALCULATOR FOR USE WITH CARISENTERS SQUARE 5 Filed Feb. 6, 1948 2Sheets-Sheet 2 Wau- ET FLPBi ars cm.

Patented Aug. 22, 1950 RAPID CALCULATOR FOR USE WITH CARPENTERS SQUAREWalter A. Peterson, King, Wis. Application February s, 1948, Serial No.6,688

2 Claims.

a l This invention relates to a device of extremely simple constructionadapted to be used with a conventional carpenters square by carpenters,painters, plasterers, lumberman, millwrights, plumbers and othertradesmen for solvin numerous mathematical problems arising inconnection with their work and which willenable such problems to besolved much more rapidly than byresorting to conventional mathematicalmethods.

' IA further object of the invention is to provide 1 a device for theaforedescribed purposes of extremely simple construction which iscapable of being economically manufactured and sold and .which willbeextremely efiicient and practical 'may be utilized for solving many ofthe problems for which a slide rule is usually employed thereby, whenutilized in conjunction with a carpenters square, affordin a rapidcalculator for use by persons not familiar with the operation of a sliderule.

Various other objects and advantages of the invention will hereinafterbecome more fully apparent from the following description of thedrawings, illustrating a presently preferred embodiment thereof, andwherein:

Figure 1 is a top plan view of the rapid calculator' for use with aconventional carpenters square; I

Figure 2 is alongitudinal sectional view thereof taken substantiallyalong a plane as indicated by the line 2-2 of Figure 1;

Figure 3 is a plan view showing the rapid calculator in afolded,'inoperative position;and,

Figures 4 and 5 are plan views showing the. rapid calculator in use witha conventional carpenters square.

Referring more specifically to the drawings, the novel rapid calculatorattachment for use "with a carpenters square and which is desigverges inone direction toward the straight edge 9 to combine therewith to formthe restricted end ll of the body 8 and which merges at its opposite endwith a curved edge l2 forming the enlarged end l3 of said body 8. Thebody 8 is divided transversely into the end sections II and 13 along theline H! and. said sections are pivo'tally connected together by'hinges15, only one of which'is illustrated, which are attached to theundersideof the body 8 and by means of which the section II can bereadily folded under the section It and so that the body 8 will assumethe appearance as seen in Figure 3. Itwill also be readily apparent thatwhen the sections H and I3 are extended, as seen in Figures '1 and 2,their adjacent edges will abut so that said sections will be disposed inthe same plane, The body 8 is provided with depending foot members I 6adapted to engage a supporting surface'for supporting the calculator lthereon and with the body 8 elevated sufiiciently so that the hinges I5will .be out of contact with said surface, not shown.

A bar or fence I! is disposed on the upper surface of the body sectionl3 and is provided with an elongated, longitudinally disposed opening 18through which the shank of a fastening l9 loosely extends. The shank ofthe fastenin I9 is threaded to engage a threaded upwardly opening recess20 in the section l3 and is provided with a wing-shaped head by means ofwhich said fastening may be readily advanced for clamping the bar llagainst the upper surface of the body section [3 or loosened to permitthe bar I! to pivot and slide on the fastening l9. The bar l! is of alength substantially equal to the width of the body 8 at its widestpoint and is provided with a straight longitudinal edge 2| which, whendisposed at a right angle to the edge 9 will extend from said edge tothe opposite edge of the body 8 when said bar is clamped relatively tothe body. With the bar I! thus disposed and as illustrated in Figure 1,it will be noted that the upper surface of said body is provided with aplurality of lines which radiate from the meeting point'of the edges 9and 2| and with each of which is associated indicia describing miters ofdifferent degrees. These lines and the'associated indicia, designat- "edgenerally 22 may be suitably inscribed in the upper surface of the body8. y

The rapid calculator 1, previously described, is intended and adapted tobe used in conjunction with a conventional carpenters square as seen at23 in Figures 4 and 5 including a blade 24 which is twenty-four inchesin length and a tongue 25 which is sixteen inches in length as isconventional. The tongue and blade are inscribed along their outer edgeswith linear measures, illustrated in inches but'commonly includingfractions of an inch up to one-sixteenth inch.

Numerous mathematical problems commonly occurring in construction workand in other operations performed by tradesmen may be quickly and easilysolved with the calculator i and carpenters square 23, one of which isillustrated in Figures 4 and 5 and wherein, for example, it is desiredto ascertain the circumference of a circle, cylinder or tank which issix inches or feet in diameter. This result can be accomplishedmathematically by multiplying the figure 6 by 3.1416 or by 122 anddividing by '7 to obtaina result which is sufiiciently close. However,by positioning the carpenters square 23 on the upper surface of the body8 as illustrated in Figure 1 and with the fence or bar I! loosened andwith the outer edge of the tongue engaging against the bar edge 2|, thecarpenter's square 23 is adjusted until the straight edge 9 intersectswith the graduation 7 of the tongue 25 and the graduation 22 of theblade 29 and with the square 23 thus disposed, as seen in Figure l, thefastening I9 is tightened for clamping the bar ll at this angle. Sincethe diameter of the tank, cylinder or circle is six, the square 23 ismoved until the graduation 6 of the tongue 25 intersects with the line9, as seen in Figure 5 and the result or circumference can then be readat the intersection point of the outer edge of the blade 24 with saidline 9 and will read 18 and 1-2 inches. This position of the bar I! maylikewise be utilized for obtaining the diameter or circumference of any"circle and it will be readily apparent that to obtain the diameter fromthe circumference the procedure is reversed and the blade 24 is adjustedso that the figure thereon representing the circumference intersectswith the straight edge 9 and when thus positioned and with the tongueagainst the bar edge 2 I, the diameter will be indicated by the point ofintersection of the outer edge of the tongue 25 with said edge 9.

To find the number of square yards in a wall,

for example, one fourteen feet wide and ten feet high, the figure 9 isemployed on the tongue of the square 23 instead of the figure 7 sincethere are nine square feet to a square yard and the figure 14, thelength of the wall is employed in lieu of the figure 22 on the blade 24and the fence or bar I1 is then set as previously described. As theheighth of the wall is ten feet the square 23 is moved until thegraduation 10 of the tongue 25 intersects the straight edge 9 and theresult can then be read on the point of intersection of the outer edgeof the blade 29 with the straight edge 9.

Assuming that a pulley twenty inches in diameter driving a smallerpulley by a belt connection has a speed of 13 revolutions per second andthat it is desired to decrease this speed to 11 revolutions per second,the square 23 is placed on the calculator l as previously described andas illustrated in Figure 4 and with the graduation 13 of the tongueintersecting the edge 9 and the graduation 20, representing the diameterof the drive pulley being used and indicated by said graduation of theblade 24 intersecting the edge 9. With the bar I! thusangularly adjustedand clamped by the fastening 19, the square 29 is then moved until thegraduation 11 of the tongue is on the straight edge 9 to indicate thedesired number of revolutions and when thus disposed,

the outer edge of the blade 24 will intersect the straight edge 9 at itsgraduation representing 16 and inches and which is the diameter of thedrive pulley required.

For solving problems in square root the figures 8 and 12 are preferablyused because the diagonal of a right angle two sides of which are each 8/2 inches or feet is 12 inches or feet, respectively and because theseare constant figures most frequently used in carpentry since 112represents the run of a rafter. Accordingly, to find the diagonal orsquare root of the sum of the two equal sides of a right angle thesquare 23 is placed as in Figure 4 but with the 8 inch graduation on thetongue intersecting the line 9 and the 12 inch graduation on the bladeintersecting said line, after which the fence or bar 11 is clamped. Bythen adjusting the square 23 so that the figure on the tongue 25 willcorrespond to the length of one side of the right angle, the hypotenuseor square root of the sum of the two right angular sides thereof can bereadily ascertained by reading the figure on the blade 24 at itsintersection point with the edge 9.

The radial lines of the indicia 22 are utilized to obtain the cut fordifferent miters and in employing the calculator l for this purpose, thefence or bar 17 is set as seen in Figure 1 at a right angle to thestraight edge 9. It will be noted as seen in Figure 1, that the uppersurface of the body 9 is inscribed with a line 29 which is disposed atright angles to the edge 9 and which meets said edge at the meetingpoint of the arcuate line of the indicia. 22 with said edge 9. With thebar I'I set as seen in Figure 1, if it is desired to obtain a hexagonmiter the square 23 is placed. on the upper surface of the body 9 withthe outer edge of the tongue 25 against the fence edge 2| and movedthereon until the graduation 12 of the blade 24 is at the intersectionof the radial hexagon miter line of the indicia 22. When thus disposedthe graduation 7 of the tongue 25 will align With the edge 9. By thenplacing the square 23 on the stock or object to be cut with the twelveinch graduation of the blade 24 and the seven inch graduation of thetongue 25 intersecting corresponding edges of said object, by cuttingthe object along the outer edge of the tongue 25 as thus disposed, thedesired miter will be obtained. By placing the square 23 in the samemanner but with the graduation 6 of the blade 24 on the pentagon line ofthe indicia 22, the 4 /2 inch line of the tongue will align with theedge 9 and by then applying the square, as previously described, to thestock or object, using the six inch mark on the blade and the four and ahalf inch mark on the tongue, the correct miter can be cut as previouslydescribed.

As previously stated, numerous other problems may be readily solved withthe calculator 1 and carpenters square 23 as only a few illustratedproblems have been herein described and various modifications andchanges in the structure of the calculator l are likewise contemplatedand may obviously be resorted to, Without departing from the spirit orscope of the invention as hereinafter defined by the appended claims,

I claim as my invention:

1. A rapid calculator attachment for use with a carpenter's squarecomprising a base having a substantially fiat top surface and providedwith a straight edge, a bar disposed on th top surface of the base, saidbar having an elongated longitudinally extending slot intermediate ofits ends, a thumbscrew extending loosely through the slot and adjustablyanchored in the base, said thumbscrew having a head disposed above thebar, said bar having a straight edge extending longitudinally thereoffor cooperatior i fvjvith the straight v e base and adaptedg to beslidably engaged b the outer edge of the tongue of a carpenter s squareand to be angularly adjusted with respectito the straight edgef of thebase by the disposition of the tongue and blade of the carquarerelatively to said straight edge base, the straight edge of the basebeing longer than either the blade or tongue of the square.'

2. A rapid calculator as in claim 1, the upper surface of said basebeinginscribed with miter indicia including lines radiating from theapex of the straight edge of the base and the straight edge of said barwhen said straight edges intersect at a right angle.

WALTER A. PETERSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

